/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.utils;

import com.badlogic.gdx.math.MathUtils;

import java.util.Arrays;

/**
 * A resizable, ordered or unordered long array. Avoids the boxing that occurs with ArrayList<Long>. If unordered, this class
 * avoids a memory copy when removing elements (the last element is moved to the removed element's position).
 *
 * @author Nathan Sweet
 */
public class LongArray {
    public long[] items;
    public int size;
    public boolean ordered;

    /**
     * Creates an ordered array with a capacity of 16.
     */
    public LongArray() {
        this(true, 16);
    }

    /**
     * Creates an ordered array with the specified capacity.
     */
    public LongArray(int capacity) {
        this(true, capacity);
    }

    /**
     * @param ordered  If false, methods that remove elements may change the order of other elements in the array, which avoids a
     *                 memory copy.
     * @param capacity Any elements added beyond this will cause the backing array to be grown.
     */
    public LongArray(boolean ordered, int capacity) {
        this.ordered = ordered;
        items = new long[capacity];
    }

    /**
     * Creates a new array containing the elements in the specific array. The new array will be ordered if the specific array is
     * ordered. The capacity is set to the number of elements, so any subsequent elements added will cause the backing array to be
     * grown.
     */
    public LongArray(LongArray array) {
        this.ordered = array.ordered;
        size = array.size;
        items = new long[size];
        System.arraycopy(array.items, 0, items, 0, size);
    }

    /**
     * Creates a new ordered array containing the elements in the specified array. The capacity is set to the number of elements,
     * so any subsequent elements added will cause the backing array to be grown.
     */
    public LongArray(long[] array) {
        this(true, array);
    }

    /**
     * Creates a new array containing the elements in the specified array. The capacity is set to the number of elements, so any
     * subsequent elements added will cause the backing array to be grown.
     *
     * @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
     *                memory copy.
     */
    public LongArray(boolean ordered, long[] array) {
        this(ordered, array.length);
        size = array.length;
        System.arraycopy(array, 0, items, 0, size);
    }

    public void add(long value) {
        long[] items = this.items;
        if (size == items.length) items = resize(Math.max(8, (int) (size * 1.75f)));
        items[size++] = value;
    }

    public void addAll(LongArray array) {
        addAll(array, 0, array.size);
    }

    public void addAll(LongArray array, int offset, int length) {
        if (offset + length > array.size)
            throw new IllegalArgumentException("offset + length must be <= size: " + offset + " + " + length + " <= " + array.size);
        addAll(array.items, offset, length);
    }

    public void addAll(long[] array) {
        addAll(array, 0, array.length);
    }

    public void addAll(long[] array, int offset, int length) {
        long[] items = this.items;
        int sizeNeeded = size + length - offset;
        if (sizeNeeded >= items.length) items = resize(Math.max(8, (int) (sizeNeeded * 1.75f)));
        System.arraycopy(array, offset, items, size, length);
        size += length;
    }

    public long get(int index) {
        if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
        return items[index];
    }

    public void set(int index, long value) {
        if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
        items[index] = value;
    }

    public void insert(int index, long value) {
        long[] items = this.items;
        if (size == items.length) items = resize(Math.max(8, (int) (size * 1.75f)));
        if (ordered)
            System.arraycopy(items, index, items, index + 1, size - index);
        else
            items[size] = items[index];
        size++;
        items[index] = value;
    }

    public boolean contains(long value) {
        int i = size - 1;
        long[] items = this.items;
        while (i >= 0)
            if (items[i--] == value) return true;
        return false;
    }

    public int indexOf(long value) {
        long[] items = this.items;
        for (int i = 0, n = size; i < n; i++)
            if (items[i] == value) return i;
        return -1;
    }

    public boolean removeValue(long value) {
        long[] items = this.items;
        for (int i = 0, n = size; i < n; i++) {
            if (items[i] == value) {
                removeIndex(i);
                return true;
            }
        }
        return false;
    }

    /**
     * Removes and returns the item at the specified index.
     */
    public long removeIndex(int index) {
        if (index >= size) throw new IndexOutOfBoundsException(String.valueOf(index));
        long[] items = this.items;
        long value = items[index];
        size--;
        if (ordered)
            System.arraycopy(items, index + 1, items, index, size - index);
        else
            items[index] = items[size];
        return value;
    }

    /**
     * Removes and returns the last item.
     */
    public long pop() {
        return items[--size];
    }

    /**
     * Returns the last item.
     */
    public long peek() {
        return items[size - 1];
    }

    public void clear() {
        size = 0;
    }

    /**
     * Reduces the size of the backing array to the size of the actual items. This is useful to release memory when many items have
     * been removed, or if it is known that more items will not be added.
     */
    public void shrink() {
        resize(size);
    }

    /**
     * Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many
     * items to avoid multiple backing array resizes.
     *
     * @return {@link #items}
     */
    public long[] ensureCapacity(int additionalCapacity) {
        int sizeNeeded = size + additionalCapacity;
        if (sizeNeeded >= items.length) resize(Math.max(8, sizeNeeded));
        return items;
    }

    protected long[] resize(int newSize) {
        long[] newItems = new long[newSize];
        long[] items = this.items;
        System.arraycopy(items, 0, newItems, 0, Math.min(items.length, newItems.length));
        this.items = newItems;
        return newItems;
    }

    public void sort() {
        Arrays.sort(items, 0, size);
    }

    public void reverse() {
        for (int i = 0, lastIndex = size - 1, n = size / 2; i < n; i++) {
            int ii = lastIndex - i;
            long temp = items[i];
            items[i] = items[ii];
            items[ii] = temp;
        }
    }

    public void shuffle() {
        for (int i = size - 1; i >= 0; i--) {
            int ii = MathUtils.random(i);
            long temp = items[i];
            items[i] = items[ii];
            items[ii] = temp;
        }
    }

    /**
     * Reduces the size of the array to the specified size. If the array is already smaller than the specified size, no action is
     * taken.
     */
    public void truncate(int newSize) {
        if (size > newSize) size = newSize;
    }

    /**
     * Returns a random item from the array, or zero if the array is empty.
     */
    public long random() {
        if (size == 0) return 0;
        return items[MathUtils.random(0, size - 1)];
    }

    public long[] toArray() {
        long[] array = new long[size];
        System.arraycopy(items, 0, array, 0, size);
        return array;
    }

    public String toString() {
        if (size == 0) return "[]";
        long[] items = this.items;
        StringBuilder buffer = new StringBuilder(32);
        buffer.append('[');
        buffer.append(items[0]);
        for (int i = 1; i < size; i++) {
            buffer.append(", ");
            buffer.append(items[i]);
        }
        buffer.append(']');
        return buffer.toString();
    }

    public String toString(String separator) {
        if (size == 0) return "";
        long[] items = this.items;
        StringBuilder buffer = new StringBuilder(32);
        buffer.append(items[0]);
        for (int i = 1; i < size; i++) {
            buffer.append(separator);
            buffer.append(items[i]);
        }
        return buffer.toString();
    }
}
